By using an RAD peptide display system derived from the ATPase domain of recombinase RadA of Pyrococcus furiosus, an anti-hCG antibody-like molecule was prepared by grafting an hCG-binding peptide to the RAD scaffold. After linking to sfGFP gene, a gene of hCG peptide-grafted RAD was synthesized and cloned into a bacterial expression vector (pET30a-RAD/hCGBP-sfGFP). The vector was transformed into Escherichia coli, and expression of the fusion protein was induced. After isolation and purification of the fusion protein, its binding affinity and specificity to hCG were determined by using a process of immunoabsorption followed by GFP fluorescence measurement. A comparison of hCG-binding activity with a similarly grafted single-domain antibody based on a universal scaffold was performed. The measurement of hCG-binding affinity and specificity revealed that the grafted RAD has an optimally high binding affinity and specificity to hCG, which are better than the grafted single-domain antibody. Moreover, the affinity and specificity of grafted RAD molecule are comparable to those of a commercial monoclonal antibody. In addition, the hCG-binding peptide-grafted RAD molecule has a relatively high biochemical stability, making it a good substitute for antibody with potential application.
Antibodies, Monoclonal ; chemistry ; isolation & purification ; metabolism ; Antibody Specificity ; DNA-Binding Proteins ; genetics ; metabolism ; Escherichia coli ; genetics ; Escherichia coli Proteins ; metabolism ; Humans ; Peptides ; Recombinant Fusion Proteins ; genetics ; metabolism

OBJECTIVE: To develop methods of extraction and purification of Cterminal NUDT9 homology domain of human transient receptor potential melastatin 2 (TRPM2) channel. METHODS: After sonication and centrifuge of strain Rosetta (DE3) which was induced by isopropylthio-β-D-galactoside, GST-NUDT9-H was collected after the binding of supernatant with GST beads and eluted with reduced glutathione. Then the elution buffer containing fusion protein was purified by size exclusion chromatography after concentration and centrifuge. Finally, with the cleavage of thrombin and binding with the GST beads, NUDT9-H with high purity in supernatant was collected. RESULTS: The GST-NUDT9-H fusion protein was stabilized with lysis buffer containing 0.5% n-dodecyl -β-d-maltoside (DDM), and wash buffer containing 0.025% DDM in size-exclusion chromatography system, and finally the NUDT9-H with high purity was obtained after cleaved by thrombin (1 U/2 mg fusion protein) for 24 h. CONCLUSIONS Due to the poor stability of NUDT9-H, it is necessary to add DDM in extraction and purification buffer to stabilize the conformation of NUDT9-H, so as to increase its yields and purity.
Escherichia coli ; genetics ; Glucosides ; chemistry ; Humans ; Protein Domains ; Protein Stability ; Pyrophosphatases ; chemistry ; genetics ; isolation & purification ; Recombinant Fusion Proteins ; chemistry ; isolation & purification ; TRPM Cation Channels ; chemistry ; isolation & purification ; Thrombin ; metabolism

Entero virus 71 (EV71) causes hand, foot, and mouth disease (HFMD) and occasionally leads to severe neurological complications and even death. Scavenger receptor class B member 2 (SCARB2) is a functional receptor for EV71, that mediates viral attachment, internalization, and uncoating. However, the exact binding site of EV71 on SCARB2 is unknown. In this study, we generated a monoclonal antibody (mAb) that binds to human but not mouse SCARB2. It is named JL2, and it can effectively inhibit EV71 infection of target cells. Using a set of chimeras of human and mouse SCARB2, we identified that the region containing residues 77-113 of human SCARB2 contributes significantly to JL2 binding. The structure of the SCARB2-JL2 complex revealed that JL2 binds to the apical region of SCARB2 involving α-helices 2, 5, and 14. Our results provide new insights into the potential binding sites for EV71 on SCARB2 and the molecular mechanism of EV71 entry.
Amino Acid Sequence ; Animals ; Antibodies, Monoclonal ; chemistry ; genetics ; metabolism ; Binding Sites ; Cell Line ; Crystallography, X-Ray ; Enterovirus A, Human ; drug effects ; genetics ; growth & development ; immunology ; Fibroblasts ; drug effects ; virology ; Gene Expression ; HEK293 Cells ; Humans ; Immunoglobulin Fab Fragments ; chemistry ; genetics ; metabolism ; Lysosome-Associated Membrane Glycoproteins ; chemistry ; genetics ; immunology ; Mice ; Models, Molecular ; Protein Binding ; Protein Conformation, alpha-Helical ; Protein Conformation, beta-Strand ; Protein Interaction Domains and Motifs ; Receptors, Scavenger ; chemistry ; genetics ; immunology ; Receptors, Virus ; chemistry ; genetics ; immunology ; Recombinant Fusion Proteins ; chemistry ; genetics ; immunology ; Sequence Alignment ; Sequence Homology, Amino Acid ; Sf9 Cells ; Spodoptera ; Thermodynamics

Chimeric antigen receptor (CAR) T cell therapy is a promising cancer treatment that has recently been undergoing rapid development. However, there are still some major challenges, including precise tumor targeting to avoid off-target or "on-target/off-tumor" toxicity, adequate T cell infiltration and migration to solid tumors and T cell proliferation and persistence across the physical and biochemical barriers of solid tumors. In this review, we focus on the primary challenges and strategies to design safe and effective CAR T cells, including using novel cutting-edge technologies for CAR and vector designs to increase both the safety and efficacy, further T cell modification to overcome the tumor-associated immune suppression, and using gene editing technologies to generate universal CAR T cells. All these efforts promote the development and evolution of CAR T cell therapy and move toward our ultimate goal-curing cancer with high safety, high efficacy, and low cost.
Cell Movement ; immunology ; Cell Proliferation ; Gene Expression ; Genetic Vectors ; chemistry ; metabolism ; Humans ; Immunotherapy, Adoptive ; methods ; Lymphocyte Activation ; Lymphocytes, Tumor-Infiltrating ; cytology ; immunology ; transplantation ; Neoplasms ; genetics ; immunology ; pathology ; therapy ; Patient Safety ; Receptors, Antigen, T-Cell ; chemistry ; genetics ; immunology ; Recombinant Fusion Proteins ; chemistry ; genetics ; immunology ; Signal Transduction ; Single-Chain Antibodies ; chemistry ; genetics ; T-Lymphocytes ; cytology ; immunology ; transplantation ; Treatment Outcome

IFT46 is one of the important components of intraflagellar transport complex B in Chlamydomonas reinhardtii, and plays important roles in the assembly, movement and perception of ciliary. To study its functional mechanism, a GST-tagged and an MBP-tagged prokaryotic expression plasmid, pGEX-2T-ift46 and pMAL-C2X-ift46 were constructed, respectively, by inserting ift46 into the pGEX-2T and pMAL-C2X vector, and then transformed into Escherichia coli BL21 (DE3) for protein expression. SDS-PAGE (15%) analysis results showed that the molecular weights of the fusion protein GST-IFT46 and MBP-IFT46 were 70 kDa and 86 kDa, respectively. We used the fusion protein GST-IFT46 purified by affinity adsorption purification (more than 95% purity) for immunity to New Zealand white rabbits. The 5th immune serum was collected and the antibody titer was determined to be 256 000 by ELISA. The antiserum was purified by Protein A affinity adsorption purification and immobilized MBP-IFT46 purification, and the specificity of polyclonal antibodies was evaluated by Western blotting and immunofluorescence. Results showed that the polyclonal antibody prepared could specifically and precisely bind IFT46 in C. reinhardtii, and IFT46 was mainly concentrated at basal body regions and few localized along the entire length of the flagellum as punctuated dots, which will make a foundation to further study the mechanism of IFT46 in cilia related diseases such as obesity, diabetes and polycystic kidney disease.
Algal Proteins ; biosynthesis ; immunology ; Animals ; Antibodies ; chemistry ; Blotting, Western ; Chlamydomonas reinhardtii ; chemistry ; genetics ; Electrophoresis, Polyacrylamide Gel ; Enzyme-Linked Immunosorbent Assay ; Escherichia coli ; Fluorescent Antibody Technique ; Intracellular Signaling Peptides and Proteins ; biosynthesis ; immunology ; Plasmids ; Rabbits ; Recombinant Fusion Proteins ; biosynthesis

To prepare virus-like particles containing FluA/B mRNA as RNA standard and control in Influenza RNA detection, the genes coding the coat protein and maturase of E. coli bacteriophage MS2 were amplified and cloned into D-pET32a vector. Then we inserted 6 histidines to MS2 coat protein by QuikChange Site-Directed Mutagenesis Kit to construct the universal expressing vector D-pET32a-CP-His. In addition, the partial gene fragments of FluA and FluB were cloned to the down-stream of expressing vector. The recombinant plasmid D-pET32a-CP-His-FluA/B was transformed to BL21 with induction by IPTG. The virus-like particles were purified by Ni+ chromatography. The virus-like particles can be detected by RT-PCR, but not PCR. They can be conserved stably for at least 3 months at both 4 degrees C and -20 degrees C. His-tagged virus-like particles are more stable and easier to purification. It can be used as RNA standard and control in Influenza virus RNA detection.
Escherichia coli ; genetics ; metabolism ; Influenza A virus ; genetics ; metabolism ; Influenza B virus ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism ; RNA, Viral ; genetics ; metabolism ; Recombinant Fusion Proteins ; genetics ; metabolism ; Ribonucleases ; chemistry ; Virion ; genetics ; metabolism

OBJECTIVETo prepare streptavidin-tagged human interferon-inducible T cell alpha chemoattractant bifunctional fusion proteins (SA/hI-TAC) and evaluate its biological activity.

METHODSpET24a-SA-hI-TAC/pET21a-hI-TAC-SA plasmids were constructed and expressed in BL21. SA-hI-TAC and hI-TAC-SA fusion proteins were purified by Ni-NTA affinity chromatography, refolded by dialysis and identified by Western blotting. The bifunctionality of the fusion proteins (biotin-binding function and hI-TAC activity) was analyzed by flow cytometry and lymphocyte chemotaxis experiment, respectively.

RESULTSSA-hI-TAC/hI-TAC-SA fusion proteins were expressed at about 12% and 25% of the total bacterial protein, respectively. The two fusion proteins had a purity of about 85% and 90% after purification, and their purity reached 98% after purification with S-100 gel filtration chromatography. Both of the fusion proteins were efficiently immobilized on the surface of biotinylated mouse bladder cancer MB49 cells (91.3% for SA-hI-TAC and 98.8% for hI-TAC-SA). SA/hI-TAC induced lymphocyte chemotaxis in a dose-dependent manner, and hI-TAC-SA showed a stronger chemotactic effect than SA-hI-TAC.

CONCLUSIONSWe successfully obtained SA/hI-TAC bifunctional fusion proteins, which may potentially be used in local treatment of tumor and as a tumor vaccine.

Animals ; Biotinylation ; Blotting, Western ; Cancer Vaccines ; Cell Line, Tumor ; Chemokine CXCL11 ; chemistry ; Chromatography, Affinity ; Humans ; Interferons ; chemistry ; Mice ; Plasmids ; Recombinant Fusion Proteins ; biosynthesis ; chemistry ; Streptavidin

OBJECTIVETo explore the mechanisms by which HFBI fusions increase recombinant fusion protein accumulation in plants.

METHODSThe HFBI sequence from Trichoderma reesei was synthesized and two plant expression vectors for expression of green fluorescence protein (GFP) and GFP-HFBI were constructed. The vectors were inoculated in Nicotiana benthamiana plants through agroinfiltration, and the expression levels and mRNA accumulation levels of GFP in Nicotiana leaves were examined by Western blotting, ELISA and RT-PCR.

RESULTSThe HFBI fusion tag significantly enhanced the accumulation of GFP in the leaves of N. benthamiana without causing toxic effects. Endoplasmic reticulum-targeted GFP-HFBI fusion induced the formation of spherical protein particles in the plant cells.

CONCLUSIONHFBI fusions can increase the accumulation of its fusion partner in plants by forming stable protein particles, which probably shields the target protein from endogenous protease-induced degadation. HFBI fusion technology provides an alternative to improving recombinant protein expression in plants from agroinfection-compatible expression vectors.

Endoplasmic Reticulum ; Genetic Engineering ; methods ; Genetic Vectors ; Green Fluorescent Proteins ; biosynthesis ; Imidazoles ; chemistry ; Plant Leaves ; metabolism ; Plants, Genetically Modified ; genetics ; metabolism ; Recombinant Fusion Proteins ; biosynthesis ; Tobacco ; genetics ; metabolism

OBJECTIVE: To express and purify NR4A1-DNA binding domain (DBD) protein of nuclear receptors. METHODS: The fusion protein PET28a-NR4A1-DBD was constructed and purified with the nickel affinity chromatography, cation-exchange chromatography and gel filtration chromatography. RESULTS: The protein PET28a-NR4A1-DBD was mostly soluable at 24 °C. A total of 2-3 mg/L pure NR4A1 proteins were yielded in bacterial culture and the purity for final fractions of NR4A1-DBD protein were great than 95% by SDS-PAGE analysis. CONCLUSION Nickel affinity chromatography is effective to purify protein. The protein purity can be further improved by the following methods including cation-exchange chromatography and gel filtration chromatography.
Electrophoresis, Polyacrylamide Gel ; Nuclear Receptor Subfamily 4, Group A, Member 1 ; chemistry ; Recombinant Fusion Proteins ; chemistry

Animals ; COS Cells ; Cercopithecus aethiops ; Endoplasmic Reticulum ; GTP Phosphohydrolases ; antagonists & inhibitors ; chemistry ; genetics ; metabolism ; GTP-Binding Proteins ; antagonists & inhibitors ; chemistry ; genetics ; metabolism ; Gene Expression ; Genetic Complementation Test ; HeLa Cells ; Humans ; Kinetics ; Membrane Fusion ; genetics ; Membrane Proteins ; antagonists & inhibitors ; chemistry ; genetics ; metabolism ; Protein Multimerization ; RNA, Small Interfering ; genetics ; metabolism ; Recombinant Proteins ; chemistry ; genetics ; metabolism ; Saccharomyces cerevisiae ; genetics ; metabolism ; Saccharomyces cerevisiae Proteins ; genetics ; metabolism ; Vesicular Transport Proteins ; genetics ; metabolism